<?php
class Student
{
    private $surname;
    private $first_name;

     private $status;
      private $course;
    private $emails;
    private $grades;

   

    function __construct($surname, $first_name,$status,$course)
    {
        $this->surname = $surname;
        $this->first_name = $first_name;
        $this->status=$status;
        $this->course=$course;
        $this->emails = array();
        $this->grades = array();
        
    }
    function add_email($which, $address)
    {
        $this->emails[$which] = $address;
    }
    function add_grade($grade)
    {
        $this->grades[] = $grade;
    }
    function average()
    {
        $total = 0;
        foreach ($this->grades as $value)
            $total += $value;
        return $total / count($this->grades);
    }
    function toString()
    {
        $result = $this->first_name . ' ' . $this->surname;
        $result .= ' (' . $this->average() .")$this->status\n".")$this->course\n" ;
        foreach ($this->emails as $which => $what)
            $result .= $which . ': ' . $what . "\n";
        $result .= "\n";
        return '<pre>' . $result . '</pre>';
    }
}